/* ============================================================
   nav.css — Side TOC, topnav, mobile menu
   ============================================================ */

/* ---------- Side TOC ---------- */
.side-toc {
  position: fixed; right: 24px; top: 50%; transform: translateY(-50%);
  z-index: 90; display: flex; flex-direction: column; align-items: center;
}
.toc-track { display: flex; flex-direction: column; align-items: center; gap: 6px; }
.toc-dot {
  position: relative; width: 8px; height: 8px; border-radius: 50%;
  background: var(--faint); border: none; display: block;
  transition: background 0.2s, transform 0.2s, width 0.2s;
  cursor: pointer;
}
.toc-dot:hover, .toc-dot.active { background: var(--teal); transform: scale(1.4); }
.toc-label {
  position: absolute; right: 20px; top: 50%; transform: translateY(-50%);
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); font-size: 0.7rem; font-weight: 500;
  padding: 3px 8px; border-radius: 6px; white-space: nowrap;
  opacity: 0; pointer-events: none; transition: opacity 0.2s;
}
.toc-dot:hover .toc-label { opacity: 1; }

/* ---------- Top Nav ---------- */
.topnav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 14px 28px;
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(8,12,24,0.75);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s;
}
[data-theme="light"] .topnav { background: rgba(248,250,252,0.85); }
.nav-logo {
  font-size: 1.25rem; font-weight: 900; letter-spacing: -1px;
  color: var(--text); text-decoration: none;
}
.nav-logo span { color: var(--teal); }
.nav-links { display: flex; gap: 28px; }
.nav-links a { color: var(--muted); font-size: 0.88rem; font-weight: 500; transition: color 0.2s; }
.nav-links a:hover, .nav-links a.active { color: var(--teal); opacity: 1; }
.nav-controls { display: flex; align-items: center; gap: 12px; }

.theme-toggle {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 6px 10px; cursor: pointer;
  font-size: 1rem; line-height: 1; transition: border-color 0.2s;
  display: flex; align-items: center;
}
.theme-toggle:hover { border-color: var(--teal); }
[data-theme="dark"] .theme-icon-light { display: none; }
[data-theme="light"] .theme-icon-dark { display: none; }

.hamburger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 4px;
}
.hamburger span {
  display: block; width: 22px; height: 2px;
  background: var(--text); border-radius: 2px; transition: all 0.3s;
}
.hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ---------- Mobile Menu ---------- */
.mobile-menu {
  position: fixed; inset: 0; z-index: 200;
  background: var(--navy); display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 32px;
  transform: translateX(100%); transition: transform 0.35s cubic-bezier(0.4,0,0.2,1);
}
.mobile-menu.open { transform: translateX(0); }
.mobile-menu-close {
  position: absolute; top: 20px; right: 24px;
  background: none; border: none; font-size: 1.4rem; color: var(--muted); cursor: pointer;
}
.mobile-menu-links { display: flex; flex-direction: column; align-items: center; gap: 20px; }
.mobile-menu-links a { font-size: 1.4rem; font-weight: 700; color: var(--text); }
.mobile-menu-links a:hover { color: var(--teal); opacity: 1; }
.mobile-menu-backdrop {
  position: fixed; inset: 0; z-index: 199;
  background: rgba(0,0,0,0.6); opacity: 0; pointer-events: none; transition: opacity 0.3s;
}
.mobile-menu-backdrop.open { opacity: 1; pointer-events: all; }